m50 serpentine belt replacement question

[brick8]

I plan on replacing the belts on my 1992 525it shortly. I am going to order them online to save $s and a trip to dealer (not my favorite place to visit). Should I also order new rollers as a preventive measure? They aren't making any noise so I am thinking I can get away without replacing them. Thanks.

[Russell]

How long have the tensioner pullies been on your car? I understand they last 60,000 miles or so before they wear.

[brick8]

Not sure, I just got the car a few months ago. Do they make noise before they break? How tough a job is this? I looked in the Bentley's and it appears I will need to first remove the fan clutch.

[yaofeng]

No need to remove the fan clutch. Inspect the belt for cracks on the ribs. Replace if you see cracks.

[Ross]

When the belt is off you can feel how the bearing in the tensioner is. If you can rock it or if it feels rough while turning or it makes noise replace it.

[Russell]

the ac belt aslo uses a tensioner pully. Check with BMA on parts cost for the ac pullly, about $17 US. One of the accessory pullies is different and would cost more. Best to call Patrick at BMA for best price/advice.

[RobPatt]

but first:
get under there with a light and draw yourself a nice little picture of the route the belt takes.....

both a/c and main belt are on tensioners, so just pop the cover on the roller, put in a 6 or 8mm hex, torque on it and the tensioner relaxes, slip the belt off, feed the new on on... slowly release the torque and the tensioner snugs it all up...

... when getting the belt on/off around the fan, you may need to twist the belt a bit so the thin side will slide past the fan and the block... you may also need to turn the fan around a bit to guide the belt off from around the fan... (just keep this in mind and when you're in there, turn the belt and then turn the fan and it'll guide it right off...).

Keep your fingers clear!
Also, your autozone or whatever should have a good belt in same metric measurement... also inexpensive and no wait for shipping...

cheers, Rob sends...


Not sure, I just got the car a few months ago. Do they make noise before they break? How tough a job is this? I looked in the Bentley's and it appears I will need to first remove the fan clutch.

[bsell]

How long have the tensioner pullies been on your car? I understand they last 60,000 miles or so before they wear.

I just bought a '95 525 (so its a M50 engine, right?) with 60K miles on it that has what sounds like an alternater bearing getting noisey. When you say the tensioner pullies wearout at 60K miles, do you mean the surface of the roller or the bearing?

I can tell you my wallet would much rather replace a tensioner w/bearing during the coming belt change than sending the alternator off for bearing/brushes work...

Brian

[Russell]

Wear is the tensioner bearings. They just seem to get nosier over time. The tensioner's surface does not seem to wear out. There are at least two types of sounds I got from mine when worn. First is a squeal when engine is cold. That goes away in 10-20 seconds. The other is a constant background 'sound when bearings are worn.

[Denton]

Wear is the tensioner bearings. They just seem to get nosier over time. The tensioner's surface does not seem to wear out. There are at least two types of sounds I got from mine when worn. First is a squeal when engine is cold. That goes away in 10-20 seconds. The other is a constant background 'sound when bearings are worn.


I'm just getting this now that it's 28F temperature outside.

Upon startup get a somewhat muted squeal for a second or two. Guess the belt is loose?

[Russell]

CRC belt conditioner seems to reduce the squeal on a cold start. Spray in on pullies and belts and it seems to stop start up squeal. Not sure how long it lasts. It is a clear thin substance that dried slightly tacky. Advance or Autozone has it for about $3.

[Denton]

CRC belt conditioner seems to reduce the squeal on a cold start. Spray in on pullies and belts and it seems to stop start up squeal. Not sure how long it lasts. It is a clear thin substance that dried slightly tacky. Advance or Autozone has it for about $3.

Thanks, I'll check into this until I can get it looked at.

[bsell]

Wear is the tensioner bearings. They just seem to get nosier over time. The tensioner's surface does not seem to wear out. There are at least two types of sounds I got from mine when worn. First is a squeal when engine is cold. That goes away in 10-20 seconds. The other is a constant background 'sound when bearings are worn.

You say 'constant background noise'. Does that noise change with engine speed?

I swear mine sounds like either the alternator or tensioner bearings. I guess I have to wait until taking delivery in January to see for sure.

[Russell]

does not seem to change with rpm. however, it is added to by other sounds so it it hard to picky out specific sounds. Just seemed quieter when the tensioners were replaced.